﻿using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace AutoExecuteSp
{
    public class ParentProcess
    {
        public static String ProcessName
        {
            get { return GetParentProcess().ProcessName; }
        }

        public static int ProcessId
        {
            get { return GetParentProcess().Id; }
        }

        public static String FullPath
        {
            get
            {
                return GetParentProcess().MainModule.FileName;
            }
        }

        public static String FileName
        {
            get
            {
                return System.IO.Path.GetFileName(GetParentProcess().MainModule.FileName);
            }
        }

        public static String DirectoryName
        {
            get
            {
                return System.IO.Path.GetDirectoryName(GetParentProcess().MainModule.FileName);
            }
        }

        private static Process GetParentProcess()
        {
            int iParentPid = 0;
            int iCurrentPid = Process.GetCurrentProcess().Id;

            IntPtr oHnd = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);

            if (oHnd == IntPtr.Zero)
                return null;

            PROCESSENTRY32 oProcInfo = new PROCESSENTRY32();

            oProcInfo.dwSize =
            (uint)System.Runtime.InteropServices.Marshal.SizeOf(typeof(PROCESSENTRY32));

            if (Process32First(oHnd, ref oProcInfo) == false)
                return null;

            do
            {
                if (iCurrentPid == oProcInfo.th32ProcessID)
                    iParentPid = (int)oProcInfo.th32ParentProcessID;
            }
            while (iParentPid == 0 && Process32Next(oHnd, ref oProcInfo));

            if (iParentPid > 0)
                return Process.GetProcessById(iParentPid);
            else
                return null;
        }

        static uint TH32CS_SNAPPROCESS = 2;

        [StructLayout(LayoutKind.Sequential)]
        public struct PROCESSENTRY32
        {
            public uint dwSize;
            public uint cntUsage;
            public uint th32ProcessID;
            public IntPtr th32DefaultHeapID;
            public uint th32ModuleID;
            public uint cntThreads;
            public uint th32ParentProcessID;
            public int pcPriClassBase;
            public uint dwFlags;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
            public string szExeFile;
        };

        [DllImport("kernel32.dll", SetLastError = true)]
        static extern IntPtr CreateToolhelp32Snapshot(uint dwFlags, uint th32ProcessID);

        [DllImport("kernel32.dll")]
        static extern bool Process32First(IntPtr hSnapshot, ref PROCESSENTRY32 lppe);

        [DllImport("kernel32.dll")]
        static extern bool Process32Next(IntPtr hSnapshot, ref PROCESSENTRY32 lppe);

    }
}
